The proposal addresses a portion of RFA NIH-NCI-DCCP-CPCB-81-1 entitled, "Mechanisms of Biological and Chemical Prevention of Carcinogenesis". Specific experiments are proposed to elucidate the mechanism of inhibition of carcinogenesis by the compounds in Category 1. three main types of experiments will be performed: (1) the effects of the chemical inhibitors on metabolism of a few arylamine, hydrazine, and nitrosamine derivatives; (2) the effect of the chemical inhibitors on the metabolic activation of the nitrogenous compounds, and (3) the effect of the chemical inhibitors on the electron transport properties of the liver microsomal cytochrome P-450-dependent monooxygenase. Lastly, the effects of the inhibitors on metabolism and metabolic activation using isolated rat hepatocytes and colon cells will be observed to further test the validity of these compounds effect on the monooxygenase. These studies will evaluate the compounds effect on the function of the monooxygenase in vitro and in vivo.